Development version of BIND 9 - 9.21.10 with meson build system

[Havard Eidnes]

> Does
> https://bind9.readthedocs.io/en/latest/chapter10.html#building-bind-9
> help?

Yes, it gets me a bit further.

The current stumbling block is that the configury system can't
find liburcu-common (despite finding the other rcu libs),
seemingly that's because the pkg-config file for that library is
somehow "missing" from the package I'm using (based on rcu
version 0.12.1).  I'm going to follow that lead further.

That said, I would still claim it's a good idea and probably also
cheap to have the build hints in e.g. a short INSTALL.md file in
the top directory in the source distribution, pointing to the
more full description via a URL and/or a file pointer.  Just a
suggestion to make life easier for folks who are coming from a
similar position as myself (I'm guessing I'm not alone).

Regards,

- Håvard